Risk Assessment

The risk assessment is a requirement that shall be performed for the application. The application risk assessment is the responsibility of the integrator. The user can also be the integrator.

The robot is partly completed machinery, as such the safety of the robot application depends on the tool/end effector, obstacles and other machines. The party performing the integration must use ISO 12100 and ISO 10218-2 to conduct the risk assessment. Technical Specification ISO/TS 15066 can provide additional guidance for collaborative applications. The risk assessment shall consider all tasks throughout the lifetime of the robot application, including but not limited to:

• Teaching the robot during set-up and development of the robot application

• Troubleshooting and maintenance

• Normal operation of the robot application

A risk assessment must be conducted before the robot application is powered on for the first time. The risk assessment is an iterative process. After physically installing the robot, verify the connections, then complete the integration. A part of the risk assessment is to determine the safety configuration settings, as well as the need for additional emergency stops and/or other protective measures required for the specific robot application.

Identifying the correct safety configuration settings is a particularly important part of developing robot applications. Unauthorized access to the safety configuration must be prevented by enabling and setting password protection.

Some safety functions are purposely designed for collaborative robot applications. These are configurable through the safety configuration settings. They are used to address risks identified in the application risk assessment.

The following limit the robot and as such can affect the energy transfer to a person by the robot arm, end effector and workpiece.

• Force and power limiting: Used to reduce clamping forces and pressures exerted by the robot in the direction of movement in case of collisions between the robot and the operator.

• Momentum limiting: Used to reduce high transient energy and impact forces in case of collisions between robot and operator by reducing the speed of the robot.

• Speed limitation: Used to ensure the speed is less that the configured limit.

The following orientation settings are used to avoid movements and reduce exposure of sharp edges and protrusions to a person.

• Joint, elbow and tool/end effector position limiting: Used to reduce risks associated with certain body parts: Avoid movement towards head and neck.

• Tool/end effector orientation limiting: Used to reduce risks associated with certain areas and features of the tool/end effector and work-piece: Avoid sharp edges being pointed towards the operator, by turning the sharp edges inward towards the robot.

Some safety functions are purposely designed for any robot application. These features are configurable through the safety configuration settings. They are used to address risks associated with the stopping performance of the robot application.

The following limit the robot stopping time and stopping distance to ensure stopping will occur before reaching the configured limits. Both settings automatically affect the speed of the robot to ensure the limit is not exceeded.

• Stopping Time Limit: Used to limit the stopping time of the robot.

• Stopping Distance Limit: Used to limit the stopping distance of the robot.

If either of the above is used, there is no need for manually performed periodic stopping performance testing. The robot safety control does continuous monitoring.

If the robot is installed in a robot application where hazards cannot be reasonably eliminated or risks cannot be sufficiently reduced by use of the built-in safety-related functions (e.g. when using a hazardous tool/end effector, or hazardous process), then safeguarding is required.

Universal Robots identifies the potential significant hazards listed below for consideration by the integrator. Other significant hazards can be associated with a specific robot application.

• Penetration of skin by sharp edges and sharp points on tool/end effector or tool/end effector connector.

• Penetration of skin by sharp edges and sharp points on nearby obstacles.

• Bruising due to contact.

• Sprain or bone fracture due to impact.

• Consequences due to loose bolts that hold the robot arm or tool/end effector.

• Items falling out of, or flying from the tool/end effector, e.g. due to a poor grip or power interruption.

• Mistaken understanding of what is controlled by multiple emergency stop buttons.

• Incorrect setting of the safety configuration parameters.

• Incorrect settings due to unauthorized changes to the safety configuration parameters.